This is the first time I’ve seen the geometry term “tesseract” used as a baby name. As Wikipedia puts it, “the tesseract is to the cube as the cube is to the square.” It’s a hypercube, basically. The word was coined in the 1880s from the Greek words tessera, “four,” and aktis, “ray.” Definitely an unusual name…though it does conveniently shorten to Tess.